Once an island of power and prosperity, Valca nui was home to many beings. Whilst connected to it's sister island things seemed to be nearly perfect until the great cataclysm when the two seperated and rose massive volcanoes ruining almost all hope for the matoran.
Unknown to the rest of the world Valca nui still went on, even when a mysterious creature arosed from the lava. Little did they know the creature opened up a vat of overheated mutagen which bound it's elemental energy to him. The beast used this power to mutate the matoran population into vicious beasts known as De-matoran.
Miraculously, with the aid of the first Toa, Teria, the last matoran still fight on, but when Teria was captured the aid of new toa were required so a special message was sent summoning Vakama, Whenua and Matau to the island where they became the Toa Valca. Unfortunately in response Tryorac sent out the two Barraki Valca Kalmah and Pridak in order to stop them.
The last matoran are bracing themselves for the ultimate battle with the De-matoran in order to gain their freedom from the clutches of Tryorac before the master volcano erupts and destroys the whole of the island and wipes off one of the key components the revival of the Great Spirit.